许恩永1，陈谕潼2，唐竞1*，杨锐2，王庚2
1.东风柳州汽车有限公司，广西 柳州 545005；2.广西大学 机械工程学院，广西 南宁 530004
摘要：通过改变汽油机配气机构的凸轮型线，控制进气门早关（early intake valve closing, EIVC）和进气门晚关（late intake valve closing, LIVC），建立米勒循环配气机构的动力学模型，对6种进气门控制策略（3种EIVC和3种LIVC）进行动力学仿真，分析和对比原机配气机构与米勒循环配气机构的动力学特性。结果表明：不同进气门控制策略下米勒循环配气机构的气门落座速度、气门落座力均小于原机；LIVC控制策略米勒循环配气机构的凸轮轴扭曲变形、凸轮与挺柱的接触应力小于EIVC控制策略；米勒循环配气机构气门落座比原机平稳，气门落座时的冲击、磨损和噪声比原机小，有利于延长配气机构的使用寿命，但米勒循环配气机构气门弹簧力和升程波动都比原机大，原机配气机构气门弹簧工作稳定性优于米勒循环。
关键词：米勒循环；配气机构；动力学对比；凸轮型线
Abstract：By changing the cam profile of a gasoline engine, the early intake valve closing (EIVC) and late intake valve closing (LIVC) of Miller cycle are achieved. The dynamic model of Miller cycle valve train is established，the dynamic simulation of 6 kinds of intake valve control strategies(3 kinds of EIVC control strategies and 3 kinds of LIVC control strategies) are carried out, the dynamic characteristics of the original engine and Miller cycle valve train are analyzed and compared. The results show that the valve seating speed and force of Miller cycle valve train under different inlet valve control strategies are less than that of the original engine. The distortion of camshaft, the contact stress between cam and tappet of LIVC control strategy are less than that of EIVC. The valve seat of Miller cycle valve train is more stable, and the impact, wear and noise during valve seating are less than that of the original engine, which is conducive to prolonging the service life of the valve train. However, the valve spring force and lift fluctuation of Miller cycle valve train are greater than that of the original engine, and the working stability of the valve spring of the original engine valve train is better than that of Miller cycle.
Keywords:Miller cycle; valve train; dynamic comparison; cam profile
|
